Liquid-liquid biphasic reactions play an important role in the chemical and pharmaceutical Industries The liquid-liquid slug flow capillary microreactor offers considerable potential benefits over the conventional liquid-liquid contactors Though the hydrodynamics and mass transfer have been investigated for this reactor concept, so fat the effective interfacial area available for mass transfer has not been experimentally quantified Despite the well-defined flow patterns arising in the capillary microreactor, the wetting behaviour of the liquids at the capillary wall is inadequately integrated into the models and thus, the true Interfacial area being used for mass transfer is uncertain